Add ability to edit profile in settings

[rebron]

Test plan

1. Visit chrome://settings/
2. Verify there is a section like Profile name and icon at the top
3. Click it; it should take you to edit profile screen

Description

Add the ability to edit profile in Settings. Create a brave://settings/editProfile page that allows users to edit their profile name and choose a Brave icon/avatar.

In the Getting Started section of Settings, add the option labeled "Profile name and icon" as the access point to brave://settings/editProfile (Chrome's equivalent is chrome://settings/manageProfile)

[kjozwiak]

@rebron is this a dupe of #4615?

[kjozwiak]

Verification PASSED on macOS 10.14.6 x64 using the following build:

Brave	0.69.128 Chromium: 77.0.3865.75 (Official Build) (64-bit)
Revision	201e747d032611c5f2785cae06e894cf85be7f8a-refs/branch-heads/3865@{#776}
OS	macOS Version 10.14.6 (Build 18G95)

• Verified the test case outlined under Add ability to edit profile in settings #5211 (comment)
• ensured that clicking on Profile name and icon opens brave://settings/manageProfile
• ensured that changing the profile icon and name under brave://settings/manageProfile propagates via the Manage People window and Profile Icon via the navigation bar
• ensured that the profile icon doesn't appear under PB and Tor windows
• Found & Created profile icons going blank/white when hovering over them #6095

Verification passed on

Brave	0.69.128 Chromium: 77.0.3865.75 (Official Build) (64-bit)
Revision	201e747d032611c5f2785cae06e894cf85be7f8a-refs/branch-heads/3865@{#776}
OS	Windows 10 OS Version 1803 (Build 17134.1006)

• Verified the test case outlined under Add ability to edit profile in settings #5211 (comment)
• ensured that clicking on Profile name and icon opens brave://settings/manageProfile
• ensured that changing the profile icon and name under brave://settings/manageProfile propagates via the Manage People window and Profile Icon via the navigation bar
• ensured that the profile icon doesn't appear under PB and Tor windows
• Encountered profile icons going blank/white when hovering over them #6095

Verification passed on

Brave	0.69.128 Chromium: 77.0.3865.75 (Official Build) (64-bit)
Revision	201e747d032611c5f2785cae06e894cf85be7f8a-refs/branch-heads/3865@{#776}
OS	Ubuntu 18.04 LTS

• Verified the test case outlined under Add ability to edit profile in settings #5211 (comment)
• ensured that clicking on Profile name and icon opens brave://settings/manageProfile
• ensured that changing the profile icon and name under brave://settings/manageProfile propagates via the Manage People window and Profile Icon via the navigation bar
• ensured that the profile icon doesn't appear under PB and Tor windows
• Encountered profile icons going blank/white when hovering over them #6095